The oncological management of head and neck tumours is well known and standardized. Radiotherapy is one of the effective tools. However, it induces major changes in healthy tissues: teeth, gums, mucous membranes, salivary glands and bones. Some, like mucositis, are immediate and often reversible; others, like hyposialia or fibrosis, are late effects and often irremediable. These changes greatly affect oral health and make its management more complex. Dental management also becomes a capital element of the care path but, unfortunately, often remains neglected by the patient but also by some practitioners. It concerns all the stages of the clinical course: initial assessment, cancer treatment itself and long-term follow-up. If neglected, the patient's quality of life will be affected and complications, sometimes serious, such as osteoradionecrosis, may occur. Specific care recommendations for maintaining oral health are mentioned, especially for those patients requiring oral cavity irradiation.